Multi-fiber cables or ribbons are being increasingly employed in a wide variety of applications. As such, several standard multi-fiber connectors have been developed and are commonly utilized. Perhaps the most common multi-fiber connector is the MT-RJ connector having a rectangular-shaped, miniature MT ferrule that was developed by Nippon Telegraph & Telephone Corporation of Tokyo, Japan. An MT-RJ connector is commonly assembled utilizing a heat cure epoxy process. In this regard, epoxy is introduced via a window defined by the mini-MT ferrule into the bores defined by the mini-MT ferrule through which the end portions of the within the ferrule. The front face of the ferrule is then polished, and the remainder of the MT-RJ connector is assembled around the pre-assembled and polished mini-MT ferrule.
With respect to the assembly of the remaining components of the MT-RJ connector, the mini-MT ferrule is mounted within a connector housing such that the front face of the ferrule is exposed. In this regard, the mini-MT ferrule includes a lengthwise extending shank and an enlarged shoulder portion proximate the rearward end of the shank. The shoulder portion is larger in lateral cross-section than the shank, thereby defining the shoulder. Upon insertion of the mini-MT ferrule into the connector housing during the assembly of an MT-RJ connector, the shoulder of the ferrule is engaged by an inwardly projecting ledge within the connector housing such that the front face of the ferrule extends outwardly beyond the connector housing, while the enlarged shoulder portion of the ferrule is retained within the connector housing. Thus, a mini-MT ferrule must include an enlarged shoulder portion to define a shoulder for engaging the connector housing.
Another common multi-fiber connector is the MT-RJ UniCam® connector available from Corning Cable Systems LLC of Hickory, N.C. The MT-RJ UniCam® connector has a modified MT ferrule referred to as the E-ferrule. The UniCam® connector can be mounted upon one or more optical fibers by means of a cam actuated mechanical splice component that permits the UniCam® connector to be field installable. In this regard, fiber stubs are typically mounted within respective bores defined by the F-ferrule. The fiber stubs are secured within the ferrule by means of an epoxy, and the front face of the ferrule is then polished. The steps of mounting the F-ferrule upon one or more fiber stubs and polishing the front face of the ferrule are performed under controlled manufacturing and assembly conditions in the factory, and the fiber stubs of the UniCam® connector are thereafter spliced onto one or more optical fibers deployed in the field. In this regard, the UniCam® connector also includes a splice component holder that engages the rearward end of the ferrule. The splice component holder defines a lengthwise extending passageway that is sized and shaped to receive a pair of splice components. The splice components define lengthwise extending grooves for receiving end portions of the fiber stubs and the optical fibers in the field. In particular, the fiber stubs upon which the ferrule is mounted extend into the grooves defined by the splice components from one end, while the optical fibers deployed in the field are inserted into the grooves defined by the splice components from the other end. By rotating a cam member relative to the splice component holder, the splice components are forced together, thereby mechanically splicing the stub fibers to the field optical fibers. Since the E-ferrule must be engaged by the splice component holder in order to ensure alignment of the stub fibers and the field optical fibers, the E-ferrule generally has a different design than the MT ferrule utilized by MT-RJ connectors. Rather than an enlarged shoulder, the E-ferrule has a reduced shoulder portion. As such, the portion of the passageway defined by the splice component holder proximate its forward end is sized and shaped to snugly receive the rearward end of the E-ferrule so that the E-ferrule and the splice component holder are maintained in an aligned relationship.
In addition to the MT-RJ connector and the MT-RJ UniCam® connector, another common multi-fiber connector is the MTP or MPO connector (hereinafter collectively referred to as the MTP connector). The MTP connector has a larger version of the MT ferrule than the MT-RJ connector and can therefore be mounted upon the end portions of a larger number of optical fibers than the MT-RJ connector. As with the MT-RJ connector, however, an MTP connector is commonly assembled by a heat cure epoxy process. In this regard, epoxy is introduced via a window defined by the MT ferrule into the bores defined by the MT ferrule through which the end portions of the optical fibers extend. The epoxy is heat cured to secure the end portions of the optical fibers within the MT ferrule. The front face of the MT ferrule is then polished, and the remainder of the MTP connector is assembled around the pre-assembled and polished ferrule.
Regardless of the type of multi-fiber connector, the connector should be capable of receiving guide pins in order to facilitate the alignment of the multi-fiber connector with another multi-fiber connector or with an optical interface device. The alignment of the multi-fiber connectors, in turn, permits alignment of the optical fibers upon which the connectors are mounted. Depending upon the type of multi-fiber connector, different guide pin retention mechanisms have been developed. With respect to the MT-RJ and MTP connectors, for example, two different configurations have been developed, namely, a male configuration that includes a pair of guide pins extending outwardly beyond the front face of the MT ferrule and a female configuration that does not include guide pins but that defines a pair of guide pin holes. A respective pair of male and female connectors is therefore mated by inserting the guide pins of a male connector into the guide pin holes of a female connector.
In order to retain the guide pins in the male configuration of the MT-RJ or MTP connector, each connector generally includes a pin keeper. During the assembly process, the guide pins are engaged by the pin keeper prior to the insertion of the guide pins into a ferrule. The pin keeper is then positioned immediately rearward of the MT ferrule with the guide pins inserted through the guide pin holes defined by the MT ferrule from the rear of the MT ferrule so as to protrude outwardly beyond the front face of the MT ferrule. Thus, the guide pins of the male configuration of an MT-RJ or MTP connector must be inserted during the pre-assembly of the ferrule in the factory and cannot be inserted in the field once the remainder of the connector has been assembled around the ferrule. As a result, the female configuration of an MT-RJ or MTP connector cannot be converted to a male configuration in the field by merely inserting guide pins through the guide pins holes defined by the MT ferrule since the guide pins will not be appropriately grasped by the pin keeper. Field technicians must therefore maintain an inventory of MT-RJ and/or MTP connectors in both the male configuration and the female configuration since the connectors cannot be converted in the field, without dissembling the connector.
Generally, MT-RJ and MTP connectors also cannot be pre-assembled. Instead, the MT-RJ and MTP connectors can only be assembled once the MT ferrule has been mounted upon the optical fibers and the front face of the MT ferrule has been polished since the guide pins of the male configuration of the connector would otherwise protrude beyond the front face of the ferrule and prevent polishing. Additionally, the MT ferrule is typically secured to the optical fibers by means of epoxy injected through a window defined by MT ferrule, thereby also preventing pre-assembly of the connector since the window must remain accessible until the optical fibers have been secured within the MT ferrule. Thus, the MT ferrule is mounted upon a plurality of optical fibers, the front face of the MT ferrule is polished, the guide pins are inserted into the guide pin holes from the rear of the ferrule for the male configuration, and the remainder of the connector is thereafter assembled. In contrast, a UniCam® connector with an E-ferrule permits the guide pins to be inserted from the front side after the front face of the E-ferrule has been polished. In this regard, the guide pins can be inserted into corresponding guide pin holes. The guide pins are then glued to the ferrule by means of epoxy injected via a pair of relatively small windows. Unfortunately, the process of gluing the guide pins to the E-ferrule is a time-consuming operation and must be carefully performed to prevent any epoxy from reaching the front face of the ferrule.
Accordingly, while various guide pin retainers have been developed for different multi-fiber connectors, an improved guide pin retainer is desired. In this regard, it would be desirable for a multi-fiber connector to be capable of being converted from a female configuration to a male configuration in the field in order to reduce the number of different connectors that a field technician must maintain in inventory. As such, it would be desirable for a multi-fiber connector to permit guide pins to be inserted from the front face of the ferrule and engaged by a guide pin retainer following assembly of the multi-fiber connector and polishing of the front face of the ferrule. Additionally, it would be desirable for a multi-fiber connector to include a guide pin retainer that permits guide pins to be inserted and engaged without the use of epoxy or the like.